This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The Stem Cell Program (Dalton) has identified Dolichos biflorus agglutinin (DBA) positive epitopes on ES cells that disappear when differentiation to EPL and EBods is induced. Lectin blotting with DBA identified 6-10 glycoproteins expressing glycans recognized by DBA. The glycoproteins expressing these glycans are being identified by excision of gel slices, trypsinization, and MALDI-TOF MS analysis. Moreover, the glycans on these glycoproteins are released, tagged with pyridylamine, and identified by chromatographic separation and MALDI-TOF MS. Initial results suggest that the DBA epitopes are on N-linked glycans because of their sensitivity to N-glycans release. Ultimately, we will answer the question of how the DBA glycan reactivity disappears after differentiation. We are identifying the glycoproteins that express this glycan and their function.